i2c: designware-pci: clarify a comment for Merrifield

There are more than 7 busses, but only 7 are user visible. Update comment
accordingly.
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-designware-pcidrv.c

@@ -125,10 +125,10 @@ static int mfld_setup(struct pci_dev *pdev, struct dw_pci_controller *c)
 static int mrfld_setup(struct pci_dev *pdev, struct dw_pci_controller *c)
 {
 	/*
-	 * On Intel Merrifield the i2c busses are enumerated [1..7]. So, we add
-	 * 1 to shift the default range. Besides that the first PCI slot
-	 * provides 4 functions, that's why we have to add 0 to the head slot
-	 * and 4 to the tail one.
+	 * On Intel Merrifield the user visible i2c busses are enumerated
+	 * [1..7]. So, we add 1 to shift the default range. Besides that the
+	 * first PCI slot provides 4 functions, that's why we have to add 0 to
+	 * the first slot and 4 to the next one.
 	 */
 	switch (PCI_SLOT(pdev->devfn)) {
 	case 8: